This invention relates to the field of special tools designed for a single purpose use. In this case, the tool is made for the specific purpose of enabling truck drivers to unlatch the coupling mechanism of semi-trailer trucks without having to reach way under the trailer to do it by hand with all of the problems and risks which that entails.
No prior art of any kind is known to the inventor of a tool that is able to do this particular function. The only presently known prior art way of doing it is by hand.
While attempting to locate prior art tools which could do this particular job, several other kinds of single purpose tools were found that were made to do other and different single purpose tasks, including the drain cock wrench disclosed in U.S. Pat. No. 2,138,725; the jack handle disclosed in U.S. Pat. No. 1,612,446; another kind of jack handle disclosed in U.S. Pat. No. 1,582,889; a complete vehicle jack and handle disclosed in U.S. Pat. No. 1,531,732; another jack with another specially designed handle for use with that particular jack disclosed in U.S. Pat. No. 1,225,822; and still another jack with a still different single purpose jack handle for use specifically with that jack as shown in U.S. Pat. No. 1,207,519. Nothing even remotely similar to a tool which can unlatch the coupling mechanism of a semi-trailer truck and at the same time hold the safety mechanism in the latch release position has been found in the prior art or known to the inventor.